If you see the dark buildings to the right of the image above, those are what used to be the Solvay Coke and Glass factory. That part is now torn down. On the left of the image is a tan-colored set of crumbling arches. Those are the basis of this exploration. The longitude and latitude coordinates of this site are 43.014490, -87.907573.
Park near 302 E Greenfield Avenue (it doesn't really matter where - since you're in the middle of the city, the police don't patrol for weird cars like they do in suburban exploration sites). There might be a fence up around where Solvay Coke and Glass used to be (that super cool graffiti-covered factory that shows up every few seconds on your Instagram feed), but if you can get around it, there's plenty of things to explore in the back. One easy way is to walk along the train tracks following the Google Map shown above until you see the two tall red-brick towers. There's a link posted below as well and GPS coordinates above.
Have you been to this site? What did you think? Leave any tips of your own or observations in the comments to help other explorers!